FYI - the best reference for what effects are is the System Parameter Manual: https://usa.yamaha.com/files/download/other_assets/1/812531/synthesizer_en_pm_c0.pdf

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Flanger
This effect creates a swirling, metallic sound.

VCM FLANGER These effects emulate the characteristics of an analog flanger used in the
1970s, recreating a warm, high-quality flanger effect.

CLASSIC FLANGER Conventional type of flanger.

TEMPO FLANGER Tempo-synchronized flanger.

DYNAMIC FLANGER Dynamically controlled flanger.

CONTROL FLANGER Manually controlled flanger.

If you search for "control flanger" in this document - you'll find various parameters with descriptions of what they do which are related to this effect:

Lower Range - [Control Flanger] Determines the minimum value of Flange Control.
Upper Range - For Control Flanger, this parameter determines the maximum value of the Flange Control.

Then there's the data list which lists all the parameters and may provide extra insight - which it doesn't exactly because the terms used here do not match. However, it's not difficult to figure out "top" as upper and "bottom" as lower, etc. Just not a wealth of information there.

Most flangers will modulate automatically. They have speed settings to control this modulation. This flanger lets you manually control the "Flanger Control" parameter so you can attach it to an expression pedal - or provide your own unique modulation pattern using an LFO, motion sequence, etc. You can tie it to the mod wheel if you want. The use of this flanger is that the rate of flange is something you can control and access in real-time.

This a well timed and interesting thread.

I was checking and playing around with the effects settings on one of the piano performances last night (I think it was a Bosendorfer one), and noticed that the first effect in the common effects area was Classic Flanger. I thought that was a bit odd to have as an effect for an acoustic grand piano. So I started changing values to see how much effect it was or wasn't having on the sound. I tried the most extreme of each setting a various times, I tried changing the flanger type to VCM, Dynamic, Control, and used various presets like "Jet', and NOTHING! It didn't make any difference to the sound. I could not make it sound like a flanger effect.
I even changed it to Phaser and tried various options and presets, but nothing. Even though the 'On' button is lit up green for that effect, it's as if it was 'Off'...

Any thoughts?

I don't think I have the Bosendorfer set loaded - so I cannot mill around to try to find the Performance you're referring to.

That said - was the effect an insertion effect or system effect (variation or reverb)? It matters slightly which since system effects have sends/returns (Var and Rev send/return) that can also squelch the effect.

Also, under the effect settings for Classic Flanger, make sure Dry/Wet is set to "DW" (or close to it). When the sign is ">", there is more dry signal than wet and "63" means all dry and no wet. "Dry" means no effect and "Wet" means with effect.

was the effect an insertion effect or system effect (variation or reverb)? It matters slightly which since system effects have sends/returns (Var and Rev send/return) that can also squelch the effect.

Also, under the effect settings for Classic Flanger, make sure Dry/Wet is set to "DW" (or close to it). When the sign is ">", there is more dry signal than wet and "63" means all dry and no wet. "Dry" means no effect and "Wet" means with effect.

I figured it out. It is on the Imperial Grand Piano and under the Master - 'Variation' (Common) for the entire Performance, it must be a 'send' as opposed to an insert, because all of the parts were set to 0 on sending to 'Variation'. As soon as I increased the parts to send to variation, I could hear the flanger.

However, a new question came to mind when looking at the effects for 'common' elements of a part. There are 2 insert effects, Ins A and Ins B, but the routing shows only that Ins A is selected for all the individual elements. Yet Ins B is also working as an effect. Maybe it's just the graphic under Routing, but it doesn't appear that Ins B is selected as an insert..!? (The options for each element under Routing are 'Ins A', 'Ins B', and 'Thru'. 'Ins A' is the one that is selected even though 'Ins B' is also being used..!?)

The routing screen is fairly well laid out. Follow the arrows. You'll see InsA always has arrows going in to it and coming out from it. Same for InsB. Those element insertions at the far left hand set up where the signal starts (after 3 band EQ). Most of the time the general routing is:

Element's Output (each) --> 3-band EQ --> InsA --> InsB --> 2-band EQ --> Variation/Reverb -> Master Effect -> Master EQ

The "Insertion Connection" usually has the routing of InsA to flow into InsB. You can also have InsB flow into InsA or have them in parallel. I'll focus on InsA->InsB because that's generally how most are setup.

On the left-hand side you don't "need" to send elements straight to InsB. InsB, from the routing shown above, gets its routing straight out of InsA. So after the InsA effect is applied - that sound, with that effect applied, will be routed into InsB.

NOW - if you did have this type of routing - any element you picked as "InsB" (instead of InsA) would only have InsB applied. This is because routing flows from InsA to InsB - and if you "plug" your element straight into InsB - then this will bypass InsA.

Hope that makes some sense.

Given the options - you can force your elements (each) to either have InsA only, or InsB only, or InsA fed into InsB, or InsB fed into InsA. Not necessarily all of them available at the same time depending on the routing topology you choose - but the system is fairly flexible for many simultaneous combinations.

FM-X has a slightly different take on effects routing. I believe most everything is available except for parallel effect routing.

Most of the time the general routing is:
Element's Output (each) --> 3-band EQ --> InsA --> InsB --> 2-band EQ --> Variation/Reverb -> Master Effect -> Master EQ

NOW - if you did have this type of routing - any element you picked as "InsB" (instead of InsA) would only have InsB applied. This is because routing flows from InsA to InsB - and if you "plug" your element straight into InsB - then this will bypass InsA.

Hope that makes some sense.

Makes perfect sense, and good to have clarification on what I suspected was the case! Thanks...

I little off the flanger topic, but regarding the final Master EQ, it's too bad that it's only 5 band with somewhat limited options for frequencies that can be chosen. It would be nice if they enhanced that particular EQ to at least 8 bands and had far more frequency options to move each band to...!

A solution that doesn't depend on Yamaha to agree with the necessity and do the development work (if it's even possible - not sure), is to use an outboard EQ. Maybe not the best solution if you're trying to carry less gear. There are programmable EQ's out there if you need to MIDI change the EQ on a Performance-by-Performance basis. I see 10 band. Lots of these are for the guitar world - but I could probably look longer and fine more generic application EQ units.